1. Field of the Invention
This invention is related to the use of insulated wires and to the use of terminals on the end of the wires to form an electrical connection. This invention is also related to the fabrication of integral terminals on bare wire ends of an insulated wire.
2. Background of the Invention
There are a number of conventional ways to terminate or connect a bare wire formed by stripping the insulation from the end of a wire. The bare wire can be soldered or spliced to another conductor. The bare wire may also be wrapped around a post or positioned under a screw, or a wire nut may be used to connect two wires.
For many applications terminals are crimped or attached to the bare wire and these terminals are then mated with a mating terminal. Conventional terminals are generally formed by either screw machining or by stamping and forming. Although terminals can provide added reliability to an electrical connection and they can simplify an operators wiring task, they do represent an additional component and an additional operation. Therefore the use of separate terminals does have some cost, including the cost to fabricate the terminal and the cost to apply the terminal. In most instances this cost is less than the advantages that can be realized by the use of pin and socket, quick disconnect tab and receptacle, blade terminals, printed circuit board terminals or any of the myriad other types of standard electrical connector terminals.
One way of fabricating conventional terminals is to stamp and form the terminals from a continuous wire having either a circular or a square cross section. Simple blade or tab configurations are easily stamped and formed using a wire blank. Cylindrical pins can also be easily fabricated in this manner. One standard method of forming printed circuit board pins that are soldered in printed circuit board holes is to use wire pins. Straight and right angle pins are often fabricated from bare wire stock. Typically some forming of pins manufactured in this manner is necessary. For example the pins can be bent and chamfer or tapered lead in sections are formed on the ends of these pins to prevent stubbing when the pins are connected to a mating receptacle connector. Some applications also require the use of pins having a first diameter on one end and a second diameter on the other end. For example, the proper diameter for use with a standard printed circuit board hole may not correspond to the desired pin diameter to interface with a standard receptacle connector terminal. One method of forming a pin having two different diameters at opposite end is to first coin a wire where the smaller diameter section is to be located. After the wire is coined, the coined section can be trimmed in a stamping operation to remove a specified amount of material. The coined and trimmed section can then be formed into a cylindrical section having a diameter that is smaller than the original diameter of the wire. Alternatively a pin having a local diameter that is to be larger than the diameter of the wire stock can be subject to a cold heading or upsetting operation to increase the local diameter by shortening the length of the local wire section. This upset section can then be formed into a cylindrical pin having a larger local diameter.